CN113249716B

CN113249716B - Laser ultrasonic powder feeding device and processing method

Info

Publication number: CN113249716B
Application number: CN202010088153.1A
Authority: CN
Inventors: 吴宏亮; 李亚萍; 秦锐; 富双超; 魏宗涛; 易俊兰
Original assignee: Shanghai Aircraft Manufacturing Co Ltd
Current assignee: Shanghai Aircraft Manufacturing Co Ltd
Priority date: 2020-02-12
Filing date: 2020-02-12
Publication date: 2023-03-31
Anticipated expiration: 2040-02-12
Also published as: CN113249716A

Abstract

The invention relates to the technical field of aerospace and discloses a laser ultrasonic powder feeding device and a processing method. The laser ultrasonic powder feeding device comprises a powder feeder assembly, wherein the powder feeder assembly is configured to convey reinforced particle mixture powder to a workpiece to be processed; the ultrasonic generator assembly is detachably connected to the powder feeder assembly and is positioned inside the powder feeder assembly, and a laser channel is arranged at the center of the ultrasonic generator assembly; the laser emission assembly is arranged above the ultrasonic generator assembly and is coaxially arranged with the powder feeder assembly and the ultrasonic generator assembly, and laser emitted by the laser emission assembly emits laser to a workpiece to be processed through a laser channel so as to generate a molten pool; the ultrasonic generator assembly is configured to generate ultrasonic vibrations to the reinforcing particulate mixture powder at the powder feeder assembly outlet and the melt pool on the workpiece to be machined. The device can improve the powder dispersion effect and strengthen the wear-resistant layer after laser processing.

Description

Laser ultrasonic powder feeding device and processing method

Technical Field

The invention relates to the technical field of aerospace, in particular to a laser ultrasonic powder feeding device and a processing method.

Background

In the service process of an airplane, the structure and accessories of the airplane can be corroded, damaged and fatigue-damaged due to the action of environment and various stresses. These failure modes often start from the local surface of the structure and then further propagate or extend into the structure, such as corrosion, wear, fatigue crack, all starting from the surface of the structure and extending into the structure. Aiming at the service performances of high wear resistance, high strength, long service life (fatigue) and the like required by parts of the airplane, the laser melt injection coupling bionic reconstruction is carried out on the easy-to-wear failure area on the surface of the parts of the airplane, a wear-resistant anti-cracking bionic structure layer is manufactured on the surface of the parts of the airplane, the wear resistance and the fatigue crack resistance of the surface of the parts of the airplane are improved, and therefore the service life of the parts of the airplane is prolonged.

The laser melting and injecting technology is a process of coaction of high-temperature light beams, reinforced particles and the surface of a parent metal. The difference between laser melting and injection and laser melting and coating is as follows: one to melt the base material to coat the reinforcing particles and one to melt the reinforcing particles to coat the surface layer of the base material. The laser melt injection technique is widely used because it can improve the matrix structure after processing and reduce the defect rate. The laser melting and injecting process is to melt partial surface of the base metal by using high temperature generated by laser, fluidize the reinforced particles by high-speed airflow and drive the reinforced particles to enter molten metal, and the molten metal is rapidly cooled after the light beam leaves. The reinforced particles are short in time of being acted by high temperature, do not melt or only melt on the surface layer, and are remained on the surface layer of the base material along with the solidification of the molten base material to form a surface modified layer with excellent wear resistance and corrosion resistance. The laser injection technology is particularly suitable for processing large-scale devices because only the surface of the parent metal is modified, thereby saving processing time and consumed materials. In laser fusion processes, the properties of the parent material are typically improved by enhancing the properties of the particles. In order to obtain a good modified surface, certain properties of reinforcement must be considered, such as chemical reaction with the parent material, melting point and ductility.

The laser melt injection process is based on the matching of a powder feeder and laser, and the residence time of the reinforced particles in high temperature needs to be strictly controlled in order to prevent the reinforced particles from being excessively melted and obtain a modified surface layer with uniform performance. At the same time, these problems are very challenging for the device stability, operational sensitivity and accuracy of the powder feeder due to the limited bath area under laser melting. Because the reinforced particles are small in size, easy to oxidize and agglomerate, difficult to store and accurately convey to a processing area, and the problem of uneven particle mixing is easy to occur during mixing and powder feeding. In actual production, a powder feeding mechanism is generally used for mixing and conveying the reinforced particles, so as to ensure the stability and continuity of particle flow during processing.

In order to solve the problems, the invention provides a laser ultrasonic powder feeding device and a processing method.

Disclosure of Invention

The invention aims to provide a laser ultrasonic powder feeding device and a processing method, which can improve the powder dispersion effect and strengthen a wear-resistant layer after laser processing.

In order to achieve the purpose, the invention adopts the following technical scheme:

provided is a laser ultrasonic powder feeding device, including:

a powder feeder assembly configured to deliver a reinforcing particulate mixture powder to a workpiece to be processed;

the ultrasonic generator assembly is detachably connected to the powder feeder assembly and is positioned in the powder feeder assembly, and a laser channel is arranged at the center of the ultrasonic generator assembly;

the laser emission assembly is arranged above the ultrasonic generator assembly and is coaxially arranged with the powder feeder assembly and the ultrasonic generator assembly, and laser emitted by the laser emission assembly emits laser to the workpiece to be processed through the laser channel so as to generate a molten pool;

the ultrasonic generator assembly is configured to generate ultrasonic vibrations to the reinforcing particulate mixture powder at the powder feeder assembly outlet and the melt pool on the workpiece to be machined.

Preferably, the ultrasonic generator assembly comprises:

a connecting plate connected to the powder feeder assembly;

and the ultrasonic transducer and the ultrasonic amplitude transformer are sequentially connected to the connecting plate along the axial direction of the powder feeder assembly, the ultrasonic transducer is configured to generate ultrasonic vibration by using electric energy, and the ultrasonic amplitude transformer is configured to amplify the ultrasonic vibration generated by the ultrasonic transducer.

Preferably, the ultrasonic transducer includes:

the powder feeder comprises a powder feeder assembly, a rear cover plate, a piezoelectric material and a front cover plate, wherein the rear cover plate, the piezoelectric material and the front cover plate are sequentially connected along the axial direction of the powder feeder assembly, the rear cover plate is connected to the connecting plate, the piezoelectric material generates ultrasonic vibration, and the front cover plate is connected to the ultrasonic amplitude transformer.

Preferably, the ultrasonic horn comprises:

the coaxial primary amplitude transformer and the coaxial secondary amplitude transformer are arranged, the primary amplitude transformer is connected with the front cover plate, and the secondary amplitude transformer is connected with the primary amplitude transformer.

Preferably, the secondary horn comprises a first shaft portion and a disc portion connected to one another, the disc portion having a diameter greater than the first shaft portion, the first shaft portion having a diameter no greater than the diameter of the primary horn.

Preferably, the powder feeder assembly comprises:

the ultrasonic generator assembly is connected to the connecting sleeve and positioned in the connecting sleeve, and outlet ends of the connecting sleeve and the powder feeding sleeve are conical;

a first preset distance is arranged between the outer wall of the connecting sleeve and the inner wall of the powder feeding sleeve to form a powder feeding channel;

and a feed inlet channel communicated with the powder feeding channel is arranged on the powder feeding sleeve.

Preferably, the feed inlet channel extends from the outer wall of the powder feeding sleeve to the outlet of the connecting sleeve along the radial direction of the connecting sleeve in an inclined manner.

Preferably, the powder feeder assembly further comprises:

the outer cone is coaxially arranged outside the powder feeding sleeve, one end of the outer cone is in threaded connection with the powder feeding sleeve, and the other end of the outer cone is conical;

a second preset distance is arranged between the inner wall of the outer cone and the outer wall of the powder feeding sleeve to form a gas channel;

and an air supply port channel communicated with the gas channel is arranged on the external cone.

Preferably, the powder feeder assembly further comprises:

the cooling cylinder body is coaxially arranged outside the outer cone, a cooling channel is formed between the cooling cylinder body and the outer cone, and a cooling medium is introduced into the cooling channel to cool the connecting sleeve, the powder feeding sleeve and the outer cone.

The invention also provides a processing method, and the laser ultrasonic powder feeding device comprises the following steps:

s1, positioning a workpiece to be processed, and adjusting the center of a laser ultrasonic powder feeding device to align to the initial processing position of the workpiece to be processed;

s2, before processing, processing information of each component is input into a control system of the laser ultrasonic powder feeding device, wherein the processing information comprises the powder feeding amount of a powder feeder component, the ultrasonic vibration frequency and the power density generated by an ultrasonic generator component, the technological parameters of laser emitted by a laser emitting component and the movement track of the laser;

s3, according to the processing information, the control system controls the laser emission assembly to emit laser to the workpiece to be processed to generate a molten pool, and meanwhile, the control system controls the powder feeder assembly to convey reinforced particle mixture powder to the workpiece to be processed and controls the ultrasonic generator assembly to generate ultrasonic vibration;

s4, stopping powder feeding of the powder feeder assembly, and continuing to work by the ultrasonic generator assembly;

and S5, stopping emitting laser by the laser emitting assembly, and quickly solidifying the molten pool.

The invention has the beneficial effects that: the ultrasonic generator assembly is positioned in the powder feeder assembly, so that the occupied space of the ultrasonic generator assembly is saved, and the whole structure is small in volume. The two components can be used as a common nozzle, and can also utilize the ultrasonic vibration effect of the ultrasonic generator component 2, and the technological parameters of the two parts are respectively adjusted according to the processing requirements without mutual interference.

Utilize powder feeder subassembly to carry reinforcing granule mixture powder to the work piece of treating processing, the laser emission subassembly is to the work piece transmission laser of treating processing, and the work piece of treating processing produces the molten bath, and ultrasonic generator subassembly produces ultrasonic vibration simultaneously, and ultrasonic vibration causes the air vibration on every side, and then can make reinforcing granule mixture powder vibration and more even that becomes to reach the effect that the reinforcing is dispersed. Meanwhile, the ultrasonic reaches the molten pool, and when the ultrasonic energy reaches a certain intensity, cavitation is generated in the molten pool in a molten state, so that the reinforced particle mixture powder floating on the surface of the molten pool can better enter the molten pool on one hand. On the other hand, the ultrasonic vibration can vibrate and stir the molten pool, a certain amount of bubbles can be eliminated, and the dispersion strengthening particle mixture powder plays a role in eliminating internal stress to a certain extent.

Drawings

FIG. 1 is a schematic illustration of the internal construction of the powder feeder assembly and ultrasonic generator assembly of the present invention;

FIG. 2 is a schematic view of the internal structure of the powder feeder assembly of the present invention;

FIG. 3 is a schematic structural view of an ultrasonic generator assembly of the present invention;

fig. 4 is a schematic structural view of an ultrasonic horn of the present invention.

In the figure: 1. a powder feeder assembly; 11. connecting sleeves; 12. powder feeding sleeve; 121. particle sheathing; 122. an inner cone; 13. an outer cone; 14. cooling the cylinder;

2. an ultrasonic generator assembly; 20. a central bore; 21. a connecting plate; 22. an ultrasonic transducer; 23. an ultrasonic horn; 221. a rear cover plate; 222. a piezoelectric material; 223. a front cover plate; 231. a first-stage horn; 232. a secondary horn; 2321. a first shaft portion; 2322. a disk portion; 30. a powder feeding channel; 40. a feed inlet channel; 50. an air supply port channel; 60. a gas channel.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that are conventionally placed when the products of the present invention are used, and are used only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements to be referred to must have specific orientations, be constructed in specific orientations, and operate, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature "on," "above" and "over" the second feature may include the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

The embodiment provides a laser ultrasonic powder feeding device which is mainly used for preparing a wear-resistant layer on the surface of a part of an airplane, wherein when the wear-resistant layer is prepared, reinforced particle mixture powder is conveyed to the surface of a workpiece to be processed, ultrasonic waves are used for dispersing the reinforced particle mixture powder, the reinforced particle mixture powder is uniformly mixed, and the wear resistance of a metal-based ceramic composite layer subjected to ultrasonic treatment is remarkably improved.

Specifically, as shown in fig. 1 to 4, the laser ultrasonic powder feeding device includes a powder feeder assembly 1, a laser emission assembly, and an ultrasonic generator assembly 2, which are coaxially disposed, wherein the ultrasonic generator assembly 2 is detachably connected to the powder feeder assembly 1 and is located inside the powder feeder assembly 1, and the laser emission assembly is disposed above the ultrasonic generator assembly 2. The powder feeder assembly 1 is configured to feed a reinforcing particle mixture powder to a workpiece to be processed, a laser channel is provided at the center of the ultrasonic generator assembly 2, and laser emitted from the laser emitting assembly emits laser to the workpiece to be processed through the laser channel to generate a molten pool. The ultrasonic generator assembly 2 is configured to generate ultrasonic vibrations to the reinforcing particulate mixture powder at the outlet of the powder feeder assembly 1 and the melt pool on the workpiece to be machined.

In this embodiment, the ultrasonic generator assembly 2 is located inside the powder feeder assembly 1, so that the occupied space of the ultrasonic generator assembly 2 is saved, and the overall structure is small in size. The two components can be used as a common nozzle, and can also simultaneously utilize the ultrasonic vibration effect of the ultrasonic generator component 2, and the technological parameters of the two parts are respectively adjusted according to the processing requirements without mutual interference.

Utilize powder feeder subassembly 1 to carry reinforcing granule mixture powder to the work piece of treating processing, the laser emission subassembly is to the work piece transmission laser of treating processing, and the work piece of treating processing produces the molten bath, and ultrasonic generator subassembly 2 produces ultrasonic vibration simultaneously, and ultrasonic vibration causes the air vibration on every side, and then can make reinforcing granule mixture powder vibration and more even that becomes to reach reinforcing dispersed effect. Meanwhile, the ultrasonic reaches the molten pool, and when the ultrasonic energy reaches a certain intensity, cavitation is generated in the molten pool in a molten state, so that the reinforced particle mixture powder floating on the surface of the molten pool can better enter the molten pool on one hand. On the other hand, the ultrasonic vibration can vibrate and stir the molten pool, a certain amount of bubbles can be eliminated, and the particle mixture powder is dispersed and enhanced, so that the effect of eliminating the internal stress is achieved to a certain extent.

The elimination of internal stress by ultrasonic vibration is mainly carried out from the following two aspects that 1. The uneven distribution of the reinforced particle mixture powder can cause partial stress concentration, and the ultrasonic vibration generated by ultrasonic waves can promote the uniform distribution of particles, thereby reducing the internal stress after the solidification of a molten pool. 2. The ultrasonic vibration action is applied to the molten pool, which can cause a certain degree of cavitation effect and mechanical effect, and can help the molten pool to have more uniform tissue and reduce pore defects in the solidification process, thereby reducing the internal stress.

In this embodiment, the material of the surface to be processed is a titanium alloy, and the reinforcing particle mixture powder is a mixture of ceramic powder and titanium alloy powder.

Specifically, fig. 1 and 2 are schematic diagrams of the internal structure of the powder feeder assembly 1 at different angles, and the powder feeder assembly 1 will be described in detail below with reference to fig. 1 and 2.

The powder feeder assembly 1 comprises a connecting sleeve 11 and a powder feeding sleeve 12 coaxially arranged outside the connecting sleeve 11, the ultrasonic generator assembly 2 is connected to the connecting sleeve 11 and is located inside the connecting sleeve 11, outlet ends of the connecting sleeve 11 and the powder feeding sleeve 12 are both conical, and a first preset distance is arranged between the outer wall of the connecting sleeve 11 and the inner wall of the powder feeding sleeve 12 to form a powder feeding channel 30.

The powder feeding sleeve 12 is provided with a feed inlet channel 40 communicated with the powder feeding channel 30, the feed inlet channel 40 is connected to an external powder feeding mechanism, in order to facilitate the reinforced particle mixture powder to flow into the powder feeding channel 30 more quickly, the feed inlet channel 40 on the powder feeding sleeve 12 also has a certain inclination angle, and the feed inlet channel 40 extends from the outer wall of the powder feeding sleeve 12 to the outlet of the connecting sleeve 11 in an inclined manner gradually along the radial direction of the connecting sleeve 11.

In a further preferred technical solution, the number of the feed inlet channels 40 is four, and the four feed inlet channels 40 are uniformly distributed in the circumferential direction of the powder feeding sleeve 12. Correspondingly, the number of the powder feeding channels 30 is four, and two adjacent powder feeding channels 30 are not communicated with each other. The four powder feeding channels 30 are uniformly distributed along the axial direction of the connecting sleeve 11, so that the powder of the reinforced particle mixture is uniformly conveyed to a workpiece to be processed, and meanwhile, the four powder feeding channels 30 are arranged to enable the powder of the reinforced particle mixture to be gathered and better melted under the action of laser.

Preferably, the largest diameter of the connecting sleeve 11 is the same as the largest diameter of the ultrasonic generator assembly 2 to facilitate the connection of the connecting sleeve 11 with the ultrasonic generator assembly 2.

On the basis of the technical scheme, the powder feeding sleeve 12 is fixedly connected with the connecting sleeve 11 through threads. The outflow of the powder mixture from the outlet of the powder feeding channel 30 is mainly controlled by an external powder storage device, and the adjustment of the size of the first preset gap at the conical area of the connecting sleeve 11 and the powder feeding sleeve 12 is realized by adjusting the threaded connection length of the powder feeding sleeve 12 and the connecting sleeve 11, so that the outflow of the powder mixture of the reinforced particles from the outlet of the powder feeding channel 30 is finely adjusted. Meanwhile, the reinforcing particle mixture powder flows out from the powder feeding passage 30 and then is gathered together, so that laser irradiation is facilitated, and the laser irradiation is performed on the gathering point of the flowing reinforcing particle mixture powder to fully melt the reinforcing particle mixture powder. The threaded connection length of the connecting sleeve 11 and the powder feeding sleeve 12 is adjusted, the size of a first preset gap can be adjusted, the adjusting range of the first preset gap is small, namely, the convergence point of the reinforced particle mixture powder can be finely adjusted in a reciprocating mode along the axial direction of the connecting sleeve 11 (the direction is up and down in practical application), the upper position and the lower position of the convergence point are adjusted, the distance between the convergence point and the emitting point of a laser beam on the path of the laser beam is different, and the reinforced particle mixture powder is caused to be different in heat.

With respect to the structure of the powder feeding sleeve 12, as shown in fig. 1 and fig. 2, the powder feeding sleeve 12 includes a particle sleeve 121 and an inner cone 122 sequentially connected along the axial direction of the connection sleeve 11, the particle sleeve 121 is sleeved outside the connection sleeve 11 and is in threaded connection with the connection sleeve 11, and the feed inlet channel 40 is disposed on the particle sleeve 121. Specifically, the inner cone 122 is threadably connected to the particle cover 121 for ease of removal, installation and maintenance.

The powder feeder assembly 1 further comprises an outer cone 13 coaxially arranged outside the powder feeding sleeve 12, one end of the outer cone 13 is in threaded connection with the powder feeding sleeve 12, and the other end of the outer cone is conical. The inner wall of the outer cone 13 and the outer wall of the powder feeding sleeve 12 are spaced by a second preset distance to form a gas channel 60, and the outer cone 13 is provided with a gas feeding channel 50 communicated with the gas channel 60. Protective gas is introduced into the workpiece region to be machined through the gas inlet channel 50 and the gas channel 60, and the protective gas is guided through the gas channel 60.

The number of the air supply port passages 50 in this embodiment is four, and the air supply port passages are uniformly distributed along the circumferential direction of the outer cone 13. Correspondingly, the number of the gas passages 60 is four, and two gas passages 60 connected with each other are not communicated. Specifically, the gas passage 60 is a cavity structure similar to a pipe.

The gas passage 60 and the powder feed passage 30 are isolated by the provision of the inner cone 122, thereby isolating the reinforcing particle mixture powder from the shielding gas.

Further preferably, as shown in fig. 1 and 2, the powder feeder assembly 1 further includes a cooling cylinder 14 coaxially disposed outside the outer cone 13, a cooling channel is formed between the cooling cylinder 14 and the outer cone 13, and a cooling medium is introduced into the cooling channel to cool the connecting sleeve 11, the powder feeding sleeve 12 and the outer cone 13.

By introducing the cooling medium into the cooling cylinder 14, the temperature of the tapered region can be reduced during long-term operation, thereby avoiding the property change of the reinforced particle mixture powder due to temperature increase and reducing the service life of the equipment.

In order to prevent leakage of the cooling medium, the cooling cylinder 14 is welded to the outer cone 13 to ensure the tightness of the cooling channel.

As shown in fig. 1, 3 and 4, the ultrasonic generator assembly 2 includes a connecting plate 21, and an ultrasonic transducer 22 and an ultrasonic horn 23 which are sequentially connected to the connecting plate 21 along the axial direction, wherein the connecting plate 21 is connected to the connecting sleeve 11, the ultrasonic transducer 22 is configured to convert electrical energy into mechanical energy, i.e., generate ultrasonic vibration, and the ultrasonic vibration generated by the ultrasonic transducer 22 causes the air around the ultrasonic transducer to vibrate. The ultrasonic horn 23 is configured to amplify the ultrasonic vibration generated by the ultrasonic transducer 22.

The ultrasonic transducer 22 includes a back cover 221, a piezoelectric material 222, and a front cover 223, which are sequentially arranged along an axial direction, the back cover 221 is connected to the connection plate 21, the piezoelectric material 222 generates ultrasonic vibration by using a piezoelectric effect, and the front cover 223 is connected to the ultrasonic horn 23.

The minimum diameter ratio of the outlet of the connecting sleeve 11 is smaller than the size of the ultrasonic amplitude transformer 23 by 7mm-8mm, so that all the reinforced particle mixture powder output from the powder feeding channel 30 can be ensured to be acted by ultrasonic vibration, and meanwhile, the reinforced particle mixture powder can be more concentrated, and waste is avoided.

The piezoelectric material 222 includes an electromagnetic coil and a piezoelectric ceramic, and the piezoelectric ceramic is placed in an electric field, and can convert electric energy into mechanical energy due to a piezoelectric effect thereof, that is, generate ultrasonic vibration.

The ultrasonic horn 23 comprises a primary horn 231 and a secondary horn 232 which are coaxially arranged, the primary horn 231 is connected with the front cover plate 223, and the secondary horn 232 is connected with the primary horn 231. The ultrasonic amplitude transformer 23 can be used for gathering energy through the two-stage amplitude transformer, and can generate cavitation in a molten pool in a molten state after the gathered energy reaches certain strength, so that the reinforced particle mixture powder floating on the surface can better enter the molten pool, and the molten pool can be vibrated and stirred to eliminate a certain amount of bubbles and disperse ceramic powder.

The secondary horn 232 includes a first shaft portion 2321 and a disk portion 2322 connected to each other, the disk portion 2322 has a diameter larger than that of the first shaft portion 2321, and the first shaft portion 2321 has a diameter not larger than that of the primary horn 231.

The ultrasonic horn 23 is of a two-stage diameter decreasing form, and compared with a one-stage type, the ultrasonic horn can reduce the occupied space on the premise of increasing the effect of ultrasonic energy, and can reduce the size of equipment. Wherein the ultrasonic horn 23 is made of the same material as the ultrasonic transducer 22.

The two-section diameter decreasing amplitude transformer is formed by connecting two round rods with different diameters. In the processing application, the ultrasonic horn 23 leaves a plane for connection at the segment, the center of the ultrasonic generator assembly 2 is provided with a center hole 20, the center hole 20 is used as a laser channel, and one end face of the secondary horn 232 close to the workpiece to be processed is in a cake shape so as to enlarge the action effect of sound energy. The diameter of the central bore 20 in this embodiment ranges from 2.5mm to 3mm.

Due to the coaxial structure, the ultrasonic action can move along with the movement of the laser track, so that the working area on the whole working path can be influenced, and the condition of ultrasonic vibration energy attenuation can not occur.

s1, positioning a workpiece to be processed, and adjusting the center of the laser ultrasonic powder feeding device to align to the initial processing position of the workpiece to be processed.

And S2, inputting the processing information of each component into a control system of the laser ultrasonic powder feeding device before processing, wherein the processing information comprises the powder feeding amount of the powder feeder component 1, the ultrasonic vibration frequency and the power density (mainly determined by the average powder feeding amount per minute) generated by the ultrasonic generator component 2, the technological parameters of the laser emitted by the laser emitting component and the movement track of the laser.

And S3, according to the processing information, the control system controls the laser emission assembly to emit laser to the workpiece to be processed to generate a molten pool, and simultaneously controls the powder feeder assembly 1 to feed the reinforced particle mixture powder to the workpiece to be processed and controls the ultrasonic generator assembly 2 to generate ultrasonic vibration. The reinforcing particle mixture powder conveyed by the powder feeder assembly 1 falls into a molten pool after dispersion treatment in air, and meanwhile, ultrasonic vibration is transmitted to the molten pool through an air medium to play a role in cavitation on the molten pool, so that the functions of assisting in stirring and dispersing reinforcing particles are achieved.

And S4, stopping powder feeding of the powder feeder assembly 1, and continuing working of the ultrasonic generator assembly 2 to generate a cavitation effect on the molten pool.

And S5, stopping emitting laser by the laser emitting assembly, rapidly condensing the liquid metal into a solid state at room temperature, condensing the dispersion-treated reinforced particle mixture powder (mixture of ceramic powder and titanium alloy powder) on the surface of the metal, and forming a composite layer consisting of ceramic metal on the surface of the workpiece, so that the strength and the wear resistance of the surface of the workpiece can be enhanced. The dispersion intensity is adjusted by changing the parameters of the generated ultrasonic vibration, so that the aim of controlling the dispersion effect of the laser melt-injection powder on the metal surface can be achieved.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A laser ultrasonic powder feeding device is characterized by comprising:

a powder feeder assembly (1), the powder feeder assembly (1) being configured to deliver a reinforcing particulate mixture powder to a workpiece to be processed;

the ultrasonic generator assembly (2) is detachably connected to the powder feeder assembly (1) and is positioned inside the powder feeder assembly (1), and a laser channel is arranged at the center of the ultrasonic generator assembly (2);

the laser emission assembly is arranged above the ultrasonic generator assembly (2) and is coaxially arranged with the powder feeder assembly (1) and the ultrasonic generator assembly (2), and laser emitted by the laser emission assembly emits laser to the workpiece to be processed through the laser channel so as to generate a molten pool;

the ultrasonic generator assembly (2) is configured to generate ultrasonic vibrations to the reinforcing particulate mixture powder at the powder feeder assembly (1) outlet and the melt pool on the workpiece to be machined;

the powder feeder assembly (1) comprises:

the ultrasonic generator comprises a connecting sleeve (11) and a powder feeding sleeve (12) coaxially arranged outside the connecting sleeve (11), the ultrasonic generator assembly (2) is connected to the connecting sleeve (11) and is positioned inside the connecting sleeve (11), and outlet ends of the connecting sleeve (11) and the powder feeding sleeve (12) are conical;

a first preset distance is arranged between the outer wall of the connecting sleeve (11) and the inner wall of the powder feeding sleeve (12) to form a powder feeding channel (30);

the powder feeding sleeve (12) is provided with a feed inlet channel (40) communicated with the powder feeding channel (30).

2. The laser ultrasonic powder feeding apparatus according to claim 1, wherein the ultrasonic generator assembly (2) comprises:

a connecting plate (21) connected to the powder feeder assembly (1);

an ultrasonic transducer (22) and an ultrasonic amplitude transformer (23) which are sequentially connected to the connecting plate (21) along the axial direction of the powder feeder assembly (1), wherein the ultrasonic transducer (22) is configured to generate ultrasonic vibration by using electric energy, and the ultrasonic amplitude transformer (23) is configured to amplify the ultrasonic vibration generated by the ultrasonic transducer (22).

3. The laser ultrasonic powder feeding apparatus according to claim 2, wherein the ultrasonic transducer (22) comprises:

the powder feeder comprises a rear cover plate (221), a piezoelectric material (222) and a front cover plate (223) which are sequentially connected along the axial direction of the powder feeder assembly (1), wherein the rear cover plate (221) is connected to the connecting plate (21), the piezoelectric material (222) generates ultrasonic vibration, and the front cover plate (223) is connected to the ultrasonic amplitude transformer (23).

4. The laser ultrasonic powder feeding device according to claim 3, wherein the ultrasonic horn (23) comprises:

the horn comprises a primary horn (231) and a secondary horn (232) which are coaxially arranged, wherein the primary horn (231) is connected with the front cover plate (223), and the secondary horn (232) is connected with the primary horn (231).

5. The laser ultrasonic powder feeder according to claim 4, wherein the secondary horn (232) comprises a first shaft portion (2321) and a disc portion (2322) coupled to each other, the disc portion (2322) having a diameter larger than a diameter of the first shaft portion (2321), the first shaft portion (2321) having a diameter not larger than a diameter of the primary horn (231).

6. The laser ultrasonic powder feeding device according to claim 1, wherein the feed inlet channel (40) extends from the outer wall of the powder feeding sleeve (12) along the radial direction of the connecting sleeve (11) and gradually inclines towards the outlet of the connecting sleeve (11).

7. The laser ultrasonic powder feeder according to claim 1 or 6, wherein the powder feeder assembly (1) further comprises:

the outer cone (13) is coaxially arranged outside the powder feeding sleeve (12), one end of the outer cone (13) is connected to the powder feeding sleeve (12) in a threaded mode, and the other end of the outer cone is conical;

a second preset distance is arranged between the inner wall of the outer cone (13) and the outer wall of the powder feeding sleeve (12) to form a gas channel (60);

an air feed channel (50) communicated with the gas channel (60) is arranged on the outer cone (13).

8. The laser ultrasonic powder feeder according to claim 7, wherein the powder feeder assembly (1) further comprises:

the cooling cylinder body (14) is coaxially arranged outside the outer cone (13), a cooling channel is formed between the cooling cylinder body (14) and the outer cone (13), and a cooling medium is introduced into the cooling channel to cool the connecting sleeve (11), the powder feeding sleeve (12) and the outer cone (13).

9. A processing method characterized by using the laser ultrasonic powder feeding apparatus according to any one of claims 1 to 8, comprising the steps of:

s2, before processing, processing information of each component is input into a control system of the laser ultrasonic powder feeding device, wherein the processing information comprises the powder feeding amount of the powder feeder component (1), the ultrasonic vibration frequency and the power density generated by the ultrasonic generator component (2), the technological parameters of laser emitted by the laser emitting component and the movement track of the laser;

s3, according to the processing information, the control system controls the laser emitting assembly to emit laser to the workpiece to be processed to generate a molten pool, and simultaneously controls the powder feeder assembly (1) to convey reinforced particle mixture powder to the workpiece to be processed and controls the ultrasonic generator assembly (2) to generate ultrasonic vibration;

s4, stopping powder feeding of the powder feeder assembly (1), and continuing to work the ultrasonic generator assembly (2);